Usually, the maab has roughly a 50% chance to paralyze an enemy, maybe a tad less. As you may know, the medic starts with a very high knife skill (around 65 base or so). After having it bumped by a martial trainer to 95 base (108 total), I got a Maab, and im paralyzing enemies roughly 80% of the time. Im tearing through cyberjäger bears with just the maab (certainly suboptimal for durability, but no other melee weapons besides 2 spores). Anyway, give it a spin. Maybe next time you get a maab it may be worth it to raise knives. Reliable paralyzation of any enemy is nothing to sneeze at!